Many pathways of primary metabolism are substantially conserved within and across plant families. However, significant differences in organization and fluxes through a reaction network may occur, even between plants in closely related genera. Assessing and understanding these differences is key to appreciating metabolic diversity, and to attempts to engineer plant metabolism for higher crop yields and desired product profiles. To better understand lipid metabolism and seed oil synthesis in canola (Brassica napus ), we have characterized four canola homologues of the Arabidopsis (Arabidopsis thaliana ) ROD1 gene. AtROD1 encodes phosphatidylcholine:diacylglycerol cholinephosphotransferase (PDCT), the enzyme that catalyzes a major flux of polyunsaturated fatty acids (PUFAs) in oil synthesis. Assays in yeast indicated that only two of the canola genes, BnROD1.A3 and BnROD1.C3 , encode active isozymes of PDCT, and these genes are strongly expressed during the period of seed oil synthesis. Loss of expression of BnROD1.A3 and BnROD1.C3 in a double mutant, or by RNA interference, reduced the PUFA content of the oil to 26.6% compared with 32.5% in the wild type. These results indicate that ROD1 isozymes in canola are responsible for less than 20% of the PUFAs that accumulate in the seed oil compared with 40% in Arabidopsis. Our results demonstrate the care needed when translating results from a model species to crop plants.

中文翻译：

---

双低油菜籽中三酰基甘油合成过程中头基交换的生物化学。

初级代谢的许多途径在植物家族内和植物家族之间基本上是保守的。但是，即使在密切相关属中的植物之间，也可能在组织和通过反应网络的通量方面发生重大差异。评估和理解这些差异是理解代谢多样性以及尝试改造植物代谢以获得更高农作物产量和所需产品特性的关键。为了更好地了解油菜（甘蓝型油菜）中的脂质代谢和种子油合成，我们对拟南芥（拟南芥）ROD1基因的四个油菜同源物进行了表征。AtROD1编码磷脂酰胆碱：二酰甘油胆碱磷酸转移酶（PDCT），该酶催化石油合成中主要的多不饱和脂肪酸（PUFA）流量。酵母中的分析表明，仅两个低芥酸菜子基因BnROD1.A3和BnROD1.C3编码PDCT的活性同工酶，并且这些基因在种子油合成期间强烈表达。BnROD1.A3和BnROD1.C3的表达缺失在双突变体中或通过RNA干扰，油中的PUFA含量降低至26.6％，而野生型为32.5％。这些结果表明，双低油菜籽中的ROD1同工酶占种子油中积累的PUFA的不到20％，而拟南芥中只有40％。我们的结果证明了将结果从模型物种转换为作物植物时需要注意的事项。